In conventional chromatographic purification workflows, it is common to perform a scouting process on a sample in a solvent mixture using an analytical system (referred to as an analytical run) before performing a purification process for isolating a target compound contained in the sample using a preparative system (referred to as a preparative run). The purpose of the analytical run is to identify the target compound and to select a suited predefined focusing gradient. For this purpose, the chromatogram from the analytical run is subdivided into several time windows.
A chemist then writes a focusing gradient for each time window for subsequent preparative runs, generally based on the chemist's experience. In a manual workflow, the user will determine, also generally based on experience, in which time window the peak of interest (of the target compound) elutes, and will assign the appropriate focusing gradient to this time window. The determination of the time window of the target compound and assignment of a predefined focusing gradient may be automated. However, using this approach, when a parameter of the chromatographic system, such as flow, column length, column inner-diameter (ID), or analytical runtime, has been changed, all predefined focusing gradients need to be adapted or completely rewritten. This process again requires involvement of an experienced chemist. Further, the number of applied time windows is usually small (e.g., three to ten time windows), which leads to a very rough classification of analytical retention times, often resulting in inappropriate selection of preparative gradients.
Accordingly, there is a need for an automated chromatographic system that does not rely upon predefined preparative focusing gradients, determined by an experienced chemist in advance, or otherwise require preparative focusing gradients to be redefined after one or more chromatographic system parameters have changed.